Mill River Union High School (Union District #40) was built by and serves the communities of Clarendon, Wallingford, and Shrewsbury. It opened in September of 1975 with a core capacity of 750 students for grades 7 through 12. Tuition students are accepted from the towns of Danby, Mt.Tabor, Tinmouth, Ira, Middletown Springs, Rutland Town, Mendon, and Chittenden. The three-town core district encompasses a wide geographical area with diverse topographical features. As of July 1, 2007 the core district population is estimated to be 6,347. The economy of the area has an emphasis on agriculture, recreational services, light manufacturing, contracting and retail sales.